Hi,
We have experience building the restaurant ordering smart phone app as well as tablet apps for ordering.
Apps does have server on LAMP platform, which allows administrators to manage menu which is categories, sub categories, items [name, images, etc], dish specific details which is like ingredients, facts, health specs etc which can be viewed by users while ordering.
Apps does have options for adding additional items to existing order and more..
We have an estimate of approx 3 to 6k based on what are your requirements.
We have experience building secure, easy to use and manage backend and interactive, well designed apps.
Look forward to work with you.
Thanks,